Definition of Cat scratch disease:

Cat scratch disease is a disease caused by bartonella bacteria. It is believed to be transmitted by cat scratches and bites, or exposure to cat saliva.

Causes, incidence, and risk factors:

Cat scratch disease is caused by Bartonella henselae. The disease is spread through contact with an infected cat (a bite or scratch), or contact with cat saliva on broken skin or the white of the eye.

About 2 - 3 weeks after becoming infected, lymph node swelling (lymphadenopathy) occurs near the site of the scratch or bite.

Occasionally, an infected lymph node may form a tunnel (fistula) through the skin and drain (leak fluid). Cat scratch disease is a common cause of chronic swollen lymph nodes in children.

Symptoms:

A person who has had contact with a cat may show common symptoms, including:

• Bump (papule) or blister (pustule) at site of injury (usually the first sign)
• Fatigue
• Fever (in some patients)
• Headache
• Lymph node swelling near the scratch or bite
• Overall discomfort (malaise)

Less common symptoms may include:

• Draining lymph nodes'
• Enlarged spleen
• Loss of appetite
• Sore throat
• Weight loss

Signs and tests:

If you have swollen lymph nodes and a scratch or bite from (or have been in contact with) a cat, the health care provider may suspect cat scratch disease. A physical examination may reveal an enlarged spleen (splenomegaly).

The disease often goes unrecognized because of the difficulty in testing. However, the Bartonella henselae IFA test is highly accurate for identifying infection caused by this bacteria.

Other tests used in the diagnosis of cat scratch disease:

• Lymph node biopsy to rule out other causes of swollen glands

Treatment:

Generally, cat scratch disease is not serious. Medical treatment is not usually needed. In severe cases, treatment with antibiotics such as azithromycin can be helpful.

In AIDS patients and other people who have a suppressed immune system, cat scratch disease is more serious, and treatment with antibiotics is recommended.

Expectations (prognosis):

In children with normal immune systems, full recovery without treatment is the norm. In immunocompromised people, treatment with antibiotics generally leads to recovery.

Complications:

• Encephalopathy
• Neuroretinitis
• Osteomyelitis
• Parinaud's syndrome (granulomatous conjunctivitis with adenopathy)

Calling your health care provider:

Call your health care provider if you have enlarged lymph nodes and a history of exposure to a cat.

Prevention:

Avoiding contact with cats prevents the disease. Where this is not reasonable, good hand-washing after playing with a cat, avoiding scratches and bites, and avoiding cat saliva will lessen the risk of infection.